Abstract—Biocompatible silica aerogel microparticles are promising drug delivery vehicles because of their large surface area and open pore structures. A simple process has been developed in this work to prepare silica aerogel microparticles from rice husk ash, using water-in-mineral oil emulsion for sol-gel, followed by aging in ethanol to strengthen gel network and drying with scCO2. This process obviates drawback of current methods for silica aerogels. The effects of speed of agitation of water-oil mixture, sol-to-oil ratio and surfactant concentration have been investigated on particle size and size distribution, BET surface area, cumulative pore volume and pore diameter. A surface area of 654 m2/g, higher than the values reported for similar materials, could be obtained.